1. Field of the Invention
The present invention relates to a bone implant, preferably a bone implant for implanting prosthetic pieces in a bone, such as dental prosthesis in a jaw, the implant comprising a fixing piece or body to be affixed in a bone and a mounting intermediate member for receiving the prosthesis piece, the mounting member being capable of being removed without traumatic effects for the patient in the event that the prosthesis or a fixing stud thereof is broken. The intermediate member can be removed even after a long time with the fixing body already integrated into the bone. Of course, the concepts of the invention are easily applied to any implant piece that must be implanted in a human being or animal bone. In addition, the invention is not only applied to expandable implants, of the type that can be initially expanded to get a retention into the bone, but also to non expandable implants.
2. Description of the Prior Art
It is well known in medical art to provide bone implants that are useful for affixing a prosthetic piece in a bone, in replacement of any lacking natural piece or member or for joining parts of one or more bones. More, particularly, these implants are well known in odontology wherein dental implants are used for replacing a dental piece that has been lost or extracted either in a human or animal patient. One of the problems or traumatic drawbacks of implanting a dental prosthesis in a patient is that a long time is necessary to assure to the patient that the implant is entirely or totally integrated to the jaw of the patient. Generally, after the extraction or loss of the dental piece, a fixing body of the implant is inserted and implanted into the jaw and several months must be awaited to determine whether the fixing body has been integrated to the bone or bone fibers of the bore in the jaw, this determination being necessary to continue or not with the next step of affixing the prosthetic piece into the implant. If the body has not been integrated the same must be replaced and a new waiting period begins again. This provokes anxiety and affliction in the patient who must await for months before receiving a positive diagnostic from the odontologist or the implantologist and upon a negative diagnostic the patient knows that the fixing body must be removed and that several additional months must be awaited again. With the purpose of shortening this waiting periods some implants, either of the expandable or non expandable type have been developed. The expandable implants are based in the theory that greater pressure against the bone generates greater bone growth. These implants are installed within the bone orifice or bore resulting from the loosen or removed dental piece or within a bore made in the bone and the implant is radially expanded in order to get a positive initial pressure and retention. During the first weeks from the installation it is possible to verify whether micro-mobility exists and, if the micro-mobility is detected the implant is additionally expanded to improve the radial retention. The purpose of these additional expansions is to get the immobility of the fixing piece that is a fundamental condition to reach the integration of the piece into the bone. While these implants have been improved insofar as the micro mobility is concerned, the same have not taken into account an important aspect of the implants, that is the need of replacing a broken prosthesis after a long time from the integration of the implant into the bone.
Generally, prosthetic dental pieces are affixed to a fixation stud or abutment that is installed by threading or adhesive within the fixing or mounting body that is already integrated into the bone. During the use of the prosthetic piece, if the fixing stud is broken within the fixing body that is already integrated or implanted, the broken portion of the stud that remains within the implanted body must be removed before a new prosthetic piece is re-installed. Any professional skilled in the art knows that the removal of this broken stud in the small room of the patient""s mouth is very difficult if not impossible. Said broken portion is not accessible and very frequently the portion cannot be extracted, therefore the implant body must be removed from its implantation by drilling the patient""s jaw to release the fixing body from the jaw bone, which is very traumatic for the patient.
The initial fixation of the implant has been treated by several professionals and disclosed in many documents like the U.S. Pat. Nos. 5,004,421 and 5,087,199 to Lazarof, which disclose expandable implants having a fixing piece that is introduced and threaded into a patient""s bone and has a hollow interior that is also threaded and a plurality of longitudinal cuts in the implant body. An expanding piece is arranged within the hollow interior, the piece being accessed from a top end of the fixing body by means of a tool that is introduced within the implant body to cause the expanding piece to rotate and move upwardly in order to expand the implant body to enhance the retention thereof into the bone. An upper portion of the fixation body has a threaded inner orifice for receiving a fixing stud or abutment of the dental prosthesis. While a better initial fixation is achieved no consideration is made to the event that the prosthesis stud is broken and the prosthesis is loosened.
U.S. Pat. No. 5,489,210 discloses a dental implant having a fixation body that is introduced within the body and has a plurality of longitudinal cuts at a lower end of the body, this lower end being expanded by an expanding piece that is introduced through an upper end into the implant body and exerts a pressure against the lower end of the body to outwardly radially expand the same against the bone. Again, the initial pressure of the implant against the bone is improved but a solution to the event of a broken stud is neither provided nor suggested. The stud of the prosthetic piece is mounted directly within the fixing body of the implant.
U.S. Pat. No. 5,611,688 discloses an expandable dental implant also comprising a hollow tubular outer body that is affixed by expansion into the bone, the expansion being obtained by an expanding screw that is inserted into the hollow body and the initial fixation of the implant is improved. This patent does not disclose any solution to the event that the prosthesis and its fixing stud are loosen or broken. In like manner, U.S. Pat. No. 5,931,674 discloses an expandable implant very similar to the ""688 patent, but no means for permitting an easy removal of a broken fixing stud are provided, and the problem is not addressed.
It would be therefore convenient to have a new expandable or non expandable implant provided with means for enhancing the initial fixation of the implant within the bone and means for permitting the easy removal of the fixation stud of the prosthesis piece in the event the stud is broken with a portion of the stud remaining within an implant body already integrated to the bone.
It is therefore one object of the present invention to provide a bone implant for fixing a dental prosthesis into a bone, the prosthesis being fixed into an implant body by means of a fixing stud that is fixed into the body, in the event the stud is broken and the prosthesis is loosened the novel implant permitting the easy removal of a portion of the stud that remains within the body without the need of removing the body from the bone.
It is still another object of the present invention to provide a bone implant comprising a fixing tubular body for fixing in the bone, the tubular body including a distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and a prosthesis piece being received in the proximal end, the bone implant comprising a mounting intermediate member for mounting said prosthesis piece, the intermediate member being removably mounted within said tubular body, the intermediate member including a proximal end in communication with an inner surface for receiving a fixing stud of said prosthesis piece.
It is a further object of the present invention to provide a bone implant comprising a fixing tubular body for fixing in the bone, the tubular body including a distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and within the gum and for receiving a prosthesis piece, the distal end of the body including a plurality of longitudinal cuts that permit a lower portion of the body be radially outwardly expanded by an expanding member that is received within said body, said expanding member being fixed to a distal end of a stem having a proximal end within said tubular body and a threaded outer surface, the implant also comprising a rotatable mounting intermediate member that includes a threaded inner surface within which said stem is threadably received, the mounting intermediate member including an upper end receiving the prosthesis piece.
The above and other objects, features and advantages of this invention will be better understood when taken in connection with the accompanying drawings and description.